"Could Troops Battle On A Terraformed MOON?" Topic

Ok. There's water on the moon.

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TMP link

Now imagine this:

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YouTube link

QUESTIONS:

Even with an atmosphere and air pressure, would troops be able to move fast and fight on Lunar ground, with so little gravity?

Also, what effect would Lunar gravity have on weaponry?

Dan

By using an utility fog stationed around the Moon (whopping big cloud of nanobots) you could keep in an atmosphere…

Presumably they would be able to move a little faster in lower gravity as they would be stronger and could go further by jumping and with each stride so the troops wouldn't tire while moving as quickly. I don't know of a reason that it would hinder forward movement.

With less gravity bullets would not fall as fast so you might be able to shoot further but grenades would fall more slowly so you might have people using them as air burst type stuff instead.

That is if you were playing sci-fi, moderns or near future.

If you were playing ancients then it is possible that catapults would have less of an effect on units as the rocks might fall slowly enough for troops to scatter around them. Arrows might fall slowly enough that only direct fire is of much utility for a similar reason.

Alternately archers might be used to engage the enemy from a much greater distance so troops would have to close more quickly or use cover more.

I don't know of a reason that it would hinder forward movement.

Friction is critical to running so normal running will be slower/harder on the moon.

I'm sure Program Manager Soldier will invent a ton (literally) of New and Improved Gear to load down the infantryman since he will be in a lower gravity environment.

There are videos on Youtube of Astronaut Jack Schmitt "running" on the moon, by hopping like a kangaroo! It's hard to estimate his speed, because he is moving towards the camera, but it looks like he's moving pretty fast. And he's encumbered by the clumsy spacesuit.

Effective friction could be increased by using shoes with spikes or cleats, so that you would gain the benefit of the lower gravity, without the downside of less friction.

I doubt that it is possible to terraform the moon though, even though there is more water than we thought, there obviously isn't that much, or it wouldn't have been so hard to detect before. Bringing water to the moon in sufficent quantities is probably impossible, even with technologies we haven't even imagined yet. More importantly, the Moon's gravity is supposed to be too weak to hold a sufficient atmosphere.

Ivan: "I doubt that it is possible to terraform the moon though, even though there is more water than we thought, there obviously isn't that much, or it wouldn't have been so hard to detect before. Bringing water to the moon in sufficent quantities is probably impossible, even with technologies we haven't even imagined yet. More importantly, the Moon's gravity is supposed to be too weak to hold a sufficient atmosphere."

But, assuming it COULD be done . . .

Would air friction and air pressure play a factor in movement and combat?

Dan

But, assuming it COULD be done . . .

Would air friction and air pressure play a factor in movement and combat?

Since you're assuming contradictory to what we know of physics, well, then, I'd have to assume that terraforming would have no effect on combat. Everything would be exactly the same, except, perhaps, the constellations.

Okay, that's a lot of mass you'd have to bring in/convert to give the moon a 1bar atmosphere at ground level. Not sure it's feasible, but let's assume we've developed cheap anti-matter or fusion or whatever as a power source that lets us do it. The moon could hold an atmosphere without any technological assistance, just not over millions of years. Gravity is gravity. Gas doesn't "fly away" on its own; it's the solar wind that strips it away, but it's a slow, gradual process.

Now, as to running, jumping etc. A 1 bar atmosphere? Sure. Why not? You're lighter and can jump farther, that's all. The main concern would be adapting to the difference. An Earth runner would probably trip all over himself as his "push off" sends him further forward than he's used to.

LOL, Jizbrand. You crack me up.

Okay. Let me rephrase that and, perhaps, clarify a bit and look at it in more scientific terms. :)

Let's just say that, instead of the entire moon, there are huge "indestructible" domes with atmosphere. If someone was to run around in atmosphere, but with the Moon's gravity, would it be any different than no atmosphere at all?

Dan

Nothing is indestructible….

Atmosphere has a big effect on weapons fire, quite a bit more so than gravity. Gravity actually has ZERO effect on bullet velocity when used against a target at the same altitude (bullet loses velocity on the way up, gets it back on the way down). Sights would have to be changed, but range would remain more or less the same. Artillery uses adjustable propellant loads, so would just need to be recalibrated at the fire control level. Grenades and other slow-moving projectiles would go a lot farther (most of their initial vector often goes into countering gravity).
As far as personal movement goes, diving for cover would be slower. Grappling would be exceedingly difficult, since you could never use any maneuver that relies on pushing downward (important for police, less so for troops, who tend to just shoot each other at close range anyway).
This would also apply in one of those "Can in the sky" several mile long colonies if the spin produced less than one g.

There was a book called 'Welcome to Moonbase' ( amazon link ) that came out in the mid-1980s. It dealt with a lot of motion issues in a low-g environment, including human-powered flight and lunar jai alai, the fastest and slowest sport in the solar system. Fastest due to ball speed, slowest due to the players.

In a colony cylinder, you need to compensate for the coriolis effect, since your target is moving.

Even with an atmosphere and air pressure, would troops be able to move fast and fight on Lunar ground, with so little gravity?

I'm not convinced this is possible. Low gravity is incompatible with high air pressure. Totally and absolutely. (You cannot just brush past it with handwavium or you might as well invent the more realistic hyperdrive and do away with the need to settle the moon in the first place.)

Even if the moon were given an atmosphere of 100% oxygen, I think it would be too diffuse to breathe. The oxygen would be at too low a pressure to cross quickly into the bloodstream. We would die of altitude sickness.

Also the moon is subject to intense solar bombardment during the "day" of 14 x 24 hours, without earth's magnetic field to properly protect it from powerful radiation. Then it has a freezing cold "night" of 14 earth days. An atmosphere would only damp that a very little bit. Nothing could grow and people would still have to walk around in suits.

The only way we could live on the moon would be in large pressurised structures (which would, of course, be easy to build in the low gravity). If they grow their own food, then all the soil would have to be imported too.

There will never be any point establishing anything other than a few bases on the Moon, to use for travel further out. It is an immensely uninviting environment. If population pressures get too much on earth, and there is no evidence they will, then we will settle hospitable places like Antarctica first.

Sorry, but it's true. We will never inhabit the Moon in any numbers.

Even with an atmosphere and air pressure, would troops be able to move fast and fight on Lunar ground, with so little gravity?

I'm not convinced this is possible. Low gravity is incompatible with high air pressure. Totally and absolutely. (You cannot just brush past it with handwavium or you might as well invent the more realistic hyperdrive and do away with the need to settle the moon in the first place.)

Even if the moon were given an atmosphere of 100% oxygen, I think it would be too diffuse to breathe. The oxygen would be at too low a pressure to cross quickly into the bloodstream. We would die of altitude sickness.

Of course it's possible. Atmospheric pressure is a function of the amount of mass which makes up an atmosphere, not the gravitational attraction of the central body— else Venus would have a lower pressure atmosphere than Earth, rather than the opposite.

It's no different than stacking weights on a scale. The more mass you add, the greater the pressure on the scale. Think about it this way. If you want a scale to read "100 kg" on Earth, you set 100 kg of weight on the scale. If you want that same scale to read "100 kg" (in Earth rates) on the moon, you set roughly 6 times that amount, or about 600 kg on the scale. You have the same amount of pressure, just more mass.

That's what would have to be done with the atmosphere on the moon; you'd just have to calculate what mass of atmosphere would be needed to achieve 1 bar pressure on the moon within a habitable range, given the moon's surface area and gravitational pull. So theoretically it's "doable." Physics does not prohibit it. Engineering is another matter…

But the question assumes the engineering is not a problem. As for that, an engineered magnetic field could "theoretically" be created as well. Of course, a 1 bar lunar atmosphere would also block a considerable amount of radiation as well.

Nothing you mention truly makes the question impossible. Unlikely, yes, but not impossible. If you can import the atmosphere, you can certainly import soil. Or just grow the food in hydroponic systems. Or import minerals to mix with lunar soil, as well as earthworms.

Now, I will agree that with our current technological capabilities, as well as any likely to be developed in the near future, no, we won't be terraforming the moon any time soon. Bases, then domes, yes, we could do, assuming we have a reason to do it. But the latter is the only real impediment; we need a reason.

For the purposes of our discussion, the environment involved only has to be the size of a game table (yeah, I know – we'll discuss the dance floors of celestial beings later). There are plenty of scenarios for a large pressurized environment with low gravity, starting with Heinlein's Loonie stories (large artificial caves in the moon), generation ships, or really big space stations. All of which are well within current physics, somewhat within current engineering, and well outside current economics. So for a Counterstrike type game with Lunar Separatists holding hostages at a location in Luna City, the commandos do have to rethink how they operate, since coming in from above is tricky (fast rope only in name), the walls and doors are either going to be paper thin screens or ultra strong pressure compartments, and anything that could start a fire (smoke grenades) is a Really Bad Idea.

Fighting in a big dome is a great idea and can be made more interesting by using unorthodox weapons.

Stun guns, water cannons, stun or flash grenades and special hand to hand weapons to compensate for the gravity change.
The reason for going down this route? If we/other had a dome colony set up do you think standard weapons would be allowed up there?.
Okay I now blame CC for a skirmish game with the tame weapons being used by a large defensive force against just a couple of gun toting maniacs who just want to damage/destroy the dome.Should be fun.

I imagine blowing holes, or shooting them in the pressure domes will be frowned upon as well.

Atmospheric pressure is a function of the amount of mass which makes up an atmosphere, not the gravitational attraction of the central body

True, sorry. However, even if we were able to generate the correct amount of oxygen and nitrogen (getting the nitrogen from where?) that much atmosphere would need continual topping up as it boiled off from the Moon's low gravity.

Nothing you mention truly makes the question impossible.

You haven't dealt with the 300 hour long days that would roast everything, followed by the 300 hour long nights that would freeze everything. Atmosphere would help reduce that, but not eliminate it entirely.

Actually adding greenhouse gases like CO2 and water would make the days much hotter, even as they reduced the nights.

This is assuming, by some miracle, you could generate a suitable protective magnetic field without an iron core. It would be a nice trick.

I think large caves are the solution. They provide protection from the Solar wind and meteorite strikes. They would keep the temperature at an even level rather than the wild 200°C swings of the surface. They would be relatively easy to carve in soft rock with low gravity. And the surface could have great big cheap nuclear power plants radiating away with no need to worry about people, providing endless power supply.

An interesting subject. I presented a paper on terraforming, once.

True, sorry. However, even if we were able to generate the correct amount of oxygen and nitrogen (getting the nitrogen from where?) that much atmosphere would need continual topping up as it boiled off from the Moon's low gravity.

Titan is a good bet, it's close to the Moon in DeltaV terms. However if we're talking macroengineering here, we may as well wrap the moon in some kind of bubble. The boiloff effect however is negligible.

This is assuming, by some miracle, you could generate a suitable protective magnetic field without an iron core. It would be a nice trick.

Lots of rare earth magnets, or magnesite deposits would do nicely.

"Okay I now blame CC for a skirmish game with the tame weapons being used by a large defensive force against just a couple of gun toting maniacs who just want to damage/destroy the dome.Should be fun."

LOL. Just constantly coming up with ways to tempt you guys, that's all. :)

Dan
By the way, rings like these could be your dome bases (some other sites have rings that are 24 inches in diameter):
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@MarkPlant: Inside a dome or cave, what's the problem?

If you're terraforming Luna, you don't need as much N2 in the atmosphere, because you need to watch the 'partial pressures'. 1000 millibars (roughly atmospheric pressure @ sea level) times .20 (O2%) is 200 millibars. O2 partial pressure should NEVER exceed 250 millibars, it becomes toxic to humans and makes fires very likely, and must ALWAYS be above 170 millibars or you go into hypoxia in a hurry).

Let's say your *total* atmospheric pressure is equivalent to 10,000ft above sea level, roughly 10 psi or 2/3rd that of sea level. The oxygen partial pressure still needs to be about 200 millibars, but the total atmospheric pressure is only 670 millibars.

Frankly, NASA space suits are only pressurized to about 5 psi (~350 millibars), so the air mix is two-thirds oxygen, one-third nitrogen.

But honestly, let's keep this indoors. Put the water tanks above the colony for radiation shielding, who needs a magnetic field?

You haven't dealt with the 300 hour long days that would roast everything, followed by the 300 hour long nights that would freeze everything. Atmosphere would help reduce that, but not eliminate it entirely.

I can think of two solutions, one low-tech, low energy, one highly-improbable tech.

Low-tech: Orbiting sun shades and mirrors, one to cool the sunward side, the other to reflect sunlight back to the "dark" side.

Really, really, high tech: Change the spin of the moon so that it rotates at a much faster rate. Again, physics does not prohibit this. How you do it (safely), I have no idea.

As for atmosphere "boiling off"… what? Gas is mass. Mass undergoes gravitational attraction. Heating the gas may expand the gas, but the mass doesn't go anywhere. It's still there, and it's still attracted to the moon. The only way for mass to "leave" is to reach lunar escape velocity— and that's true whether the mass in question is a molecule of rock or a molecule of oxygen. The moon's atmosphere can't be "boiled off." (Else we'd ditch the rockets and leave our own planet in nothing but glorified hot air balloons.) But the atmosphere can be stripped off, gradually, by the solar wind as it impacts the atmosphere, imparting velocities greater than lunar escape velocity… but that's gonna take a really, really, really long time.

So yep, a stable, reasonable temperature, fully "atmosphered" moon is possible.

Again, why anyone would do all this, and how they'd go about doing any of it, well, that's beyond my pay grade. But it could be done.

As for atmosphere "boiling off"… what? … The moon's atmosphere can't be "boiled off."

But the atmosphere can be stripped off, gradually, by the solar wind as it impacts the atmosphere, imparting velocities greater than lunar escape velocity…

AFAIK, "boiling-off" is a common term for what you describe next. Though I suppose "evaporating off" is more appropriate.

Let's see here: projectile weapons are going to be less-than-appreciated in a dome, unless you put a whole lot of lunar concrete over the top. That *should* be there, as a radiation shield, so there's little risk of puncturing the dome with small-caliber weapons fire (5.7x28, 5.56NATO). There's a higher chance that the counter-terrorists will be using safety slugs (aka frangible rounds).

Due to the low gravity, ballistic trajectories are going to be weird, but since large parts of this will be at very close ranges (<25m), it's going to be of negligible effect.

Explosives and anything that can cause a fire would be tightly restricted. Submariners are the closest thing to astronauts and we have a horrible fear of fires (see USS Bonefish, see also USS Forrestal). Just a whiff of smoke and we attack almost without conscious thought.

Movement would be really weird: that low gravity means your push-off from running bounces you up high in the air, and it takes you longer to come down. You also have a lot more mass (suit+armor), so you're much less maneuverable than you're used to.